Manufacture of enameled ware.



UNITED STATES Patented April 26, 1904.

P TENT, @EEIcE,

NTHOMAS MAsoN LUNAN, OF NEWARK, NEW JERSEY, ssIcrNon TO THE CENTRAL sTAMPINor COMPANY, OF NEW YORK, A cOsPonATIoN OF NEW YORK.

MANUFACTURE OF ENAMELED WA-RE.

SPECIFICATION forming part of Letters Patent No. 758,325, dated April 26, 1904.

* Application filed March 28, 1903. i Serialllo. 150,040. (No specimens.) i

To (Ll/[T- whom it may concern.-

Be it known that I, THOMAS MASON LUNAN, a citizen of the United States, residing at Newark, county of Essex, State of New Jersey, have invented certain new and useful Improvements in the Manufacture of Enameled are, of which the following is aspecitication.

My invention consists in a process of enameling metal ware.

The object of my invention is to produce enameled ware which will have a. hard firm cohesive coating of attractive appearance and which owing to the acid character of the enamel will not be acted upon by acids or similar decomposing agents, as is the case where the enamel is of alkaline character.

' To carry my invention into effect, I proceed as follows: The article to be enameled is first annealed and subsequently cleaned in any well-known manner. After all the grease and dirt have been removed and the article dried it is dipped into a solution of potassium chlorate or sodium chlorate or other strong oxidizing solution. Potassium chlorate, as is well-known, is one of the strongest oxidizing agents, and this body in the subsequent operation of baking to which the enameled artide is subjected and even before breaks up according to the formula KGlO3 I Cl-l-3O. The nascent oxygen set free attacks the metal body of. the article on which the enamel is to be applied, permeates it for a short distance, and forms a roughened surface, which forms an excellent point of attachment for the enamel. The oxygen also converts all ferrousiron present in the composition .of the enamel to ferric iron, and, further, raises all other metals present to a state of oxidation. This step I consider of advantage. It may, however, be entirely omitted. After the article to be enameled has been cleaned or after it has been subjected to treatment with the oxidizing solution, as above described, it is coated with an enamel of a distinctly acid nature, such as may be made by mixing vari ous bodiesas, for instance, feldspar, silicic acid, calcium triphosphate, sodium carbonate, sodium tetraborate, and calcium fiuorid with,

if it is desired, the addition of suitable coloring reagentsas, for instance, cobalt oxid care being taken in compounding this coating to have the acidic part of the reagents in excess of the basic oral kaline part. This" enamel after smelting is ground and brought to the desired consistency by the addition of clay or other suitable thickening reagent. The coating may be applied by'dipping or otherwise. The article to be enameled may now be placed in the usual 'mufile and heated to set the enamel, or, preferably, in order to give the enamel an attractive mottled or foliated appearance there is applied in the form of a spray or otherwise a solution of ammonium hydroxid or other non-metallic hydroxid, such as phenyl hydrozine. I do not limit myself, however, to non-metallic hydroxide. The chemical action which takes place between the metallic bodies carried by the constituents of the enamel and the ammonium hydroxid are as follows for ferrous iron, ferric iron, and aluminium:

Feso,+2NInOH:Ee(OH)2+(NPI.),sO. EeasooacNmOH:2Ee(OII),+3(NII.),so.

These hydrated oxids form masses throughout the body of the enamel which greatly enhance the beauty of the article when finished. After this treatment the article may be baked in a muffle in the usual manner. I Vhen the article is finished, it is covered with a beautifully-mottled and completely-oxidized enameled mass which by reason of its acid char actor will resist the action of all decomposing agents,in marked contrast to the behavior of ware coated with alkaline enamel, which, as

is well known, is easily attacked by acids because of the excess of the basic radicals which combine with the attacking acids forming their respective metallic salts, which in turn dissolve, thus allowing the enamelto easily disintegrate.

I make no claim in this application for the article of manufacture resulting from the process described, as the same has been made the subject of another application, Serial No. 195,229, filed February 25, 1904:.

Having thus described my invention, I claim 1. The herein-described process of enameling, which consists in coating the cleaned article with an enamel carrying metallic bodies and acid in character, then applying to said enameled surface a non-metallic hydroxid, and finally heating to flux and set the enamel.

2. The herein-described process of enameling, which consists in coating the cleaned article with an acid enamel of a character which will not attack the metal of which the article is made, and while still moist with a non-metallic hydroxid, and finally heating to flux and set the enamel.

8. The herein-described process of enameling which consists in coating the cleaned article with an acid enamel, and while still moist with a non-metallic hydroxid and finally heating to flux and set the enamel.

4. The herein-described process of enameling, which consists first in subjecting the cleaned article to the action of an oxidizing agent which will attack the metal of which the article is made, then applying a coating of acid enamel, then applying while the enamel is still moist a non-metallic hydroxid, and finally heating to flux and set the enamel.

5. The herein-described process of enameling which consists first, in subjecting the cleaned article to the action of an oxidizing agentwhich will attack themetal, then applying a coating of acid enamel, then applying to said coating a non metallic hydroxid, and finally heating to flux and set the enamel.

6. The herein-described process of enameling which consists first, in subjecting the cleaned article to the action of a solution of potassium chlorate, then applying a coating of acid enamel; then applying to said coating enamel as masses, throughout the whole body of the enamel, and finally heating to flux and set the enamel.

In testimony whereof I afiix my signature in the presence of two witnesses.

Witnesses:

J. E. PEARSON, FRANK OCoNNoR.

THOMAS MASON LUNAN. 

